Ion acceleration system for medical and/or other applications

ABSTRACT

The ion acceleration system or complex (T) for medical and/or other applications is composed in essence by an ion source ( 1 ), a pre-accelerator ( 3 ) and one or more linear accelerators or linacs ( 6, 8, 10, 13 ), at least one of which is mounted on a rotating mechanical gantry-like structure ( 17 ). The isocentrical gantry ( 17 ) is equipped with a beam delivery system, which can be either ‘active’ or ‘passive’, for medical and/or other applications. The ion source ( 1 ) and the pre-accelerator ( 3 ) can be either installed on the floor, which is connected with the gantry basement, or mounted, fully or partially, on the rotating mechanical structure ( 17 ). The output beam can vary in energy and intensity pulse-by-pulse by adjusting the radio-frequency field in the accelerating modules of the linac(s) and the beam parameters at the input of the linear accelerators.

FIELD OF THE INVENTION

The present invention relates to a complex or system of particleaccelerators, which includes one or more linear accelerators (linacs)according to the preamble of claim 1.

BACKGROUND OF THE INVENTION

It is known that hadron therapy is the modern cancer teletherapy thatuses beams either of protons or of heavier nuclear charged particleswith mass number larger than 1.

It is equally known that in protontherapy, which is a particular hadrontherapy technique based on the use of proton beams, therapeutic beams ofrelatively low current (of the order of some nanoamperes) are used, withenergies in the range 60 to 250 MeV.

It is also known that, in the case of different ion species, therapeuticbeams with lower currents and higher energies are required compared tothe ones for the protons. For example, in the case of carbon ions ¹²C⁶⁺,the required energies are between 1.500 and 5.000 MeV (i.e. 120 and 450MeV/u) and currents of a fraction of nanoampere.

In this field of teletherapy different types of accelerators are used:cyclotrons (isochronous or synchrocyclotrons; conventional orsuperconducting) or synchrotrons.

Recently Fixed Field Alternating Gradient (FFAG) accelerators have alsobeen considered.

Linear accelerators (linacs) have been proposed by the Requestor forboth proton and light ion therapy. 1) U.S. Pat. No. 6,888,326 B2 “Linacfor Ion Beam Acceleration, U. Amaldi, M. Crescenti, R. Zennaro. 2) U.S.patent application Ser. No. 11/232,929 “Ion Accelerator System forHadrontherapy, Inventors: U. Amaldi, M. Crescenti, R. Zennaro, filed on23, Sep. 2005. 3) “Proton Accelerator Complex for Radio-isotopes andTherapy, U. Amaldi, filed on 24. Apr. 2006.

Several companies offer turn-key centres for proton and/or carbon iontherapy. Typically a centre for more than 400-500 patients/year islocated in a large multi-floor building, specially made to host thehigh-tech apparata, offices and services for the personnel and thereception of the patients for a total surface of many thousands squaremetres. It features a hadron accelerator (cyclotron, synchrocyclotron,synchrotron, linac or a combination of these) and a system of magneticbeam transport channels to irradiate solid tumours with 2-4 gantries,which rotate around the patient, and one or more horizontal therapeuticbeams. A complete multi-room centre with its infrastructures requires aninvestment that is in the range 60-130 million Euro, the larger figurecorresponding to a ‘dual’ carbon ion and proton multi-room facility.

Hadron therapy has a large potentiality of further developments, asindicated by the epidemiological studies performed in Austria, France,Italy and Germany, that have been reported, for example, in “Carbon iontherapy, Proceedings of the HPCBM and ENLIGHT meetings held in Baden(September 2002) and in Lyon (October 2003)” [Radiotherapy and Oncology73/2 (2004) 1-217]. However these potentialities are hindered by thenecessity of large capital investments to construct multi-roomfacilities. The potentialities can be summarized by recalling that thequoted studies reach the conclusion that in the medium-long term about12% (3%) of the patients treated today with ‘conventional’ radiotherapy(i.e. with high-energy photons) would be better cured and/or have lesssecondary effects if they could be irradiated with proton (carbon ion)beams.

Only 1-2% of the 12% tumour indications for proton therapy are acceptedby most radiation oncologists. The other 10% of the patients is notconsidered today as carrying elective indications for proton therapy bymany specialists. This in spite of the fact that they would certainlyprofit from this irradiation modality, since the tumours are close tocritical organs and it is proven that a 10% increase in the dose—for thesame irradiation of critical organs—implies a 15-20% increase of theTumour Control Probability (TCP). However it is sure that, with theaccumulation of clinical trials, the first fraction of the patients willincrease and the second one decrease.

For ion therapy, which is a qualitatively different type of radiation(because in each traversed cellular nucleus a carbon ion leaves 20 timesmore energy than a proton having the same range) further clinicalstudies are needed. It is in fact necessary to confirm that on‘radioresistant’ tumours ions are more effective than photons andprotons and that it is clinically safe to reduce the number of treatmentsessions (ipo-fractionation). From other points of view such an approachis certainly advantageous since it implies a reduction of the costs andof the psychological burden to the patient.

Starting from these figures—and taking into account that in a populationof 10 million and in a year about 20,000 patients are irradiated withphotons—the number of hadron therapy treatment rooms needed withinfive/ten years are shown in the table. Two simplifying hypotheses havebeen made on the basis of clinical experience: (1) the number ofsessions per patients scales as 1:2:3 for ions, protons and photons,respectively and (2) a photon (hadron) session lasts 15 min (20 min).

Pts. per Rooms per year in Average No. Sessions per Pts per year Roomsper 10 million Radiation 10⁷ of sessions day (12 h) (230 d) 10 millionpeople treatment people per patient in one room in one room peopleFactor ≈ Photons 20   30 48 370 54  8² 10³ Protons 2.4 20 36 410 5.8 8(12%) 10³ C ions 0.6 10 36 830 0.7 1 (3%) 10³

The estimated numbers of rooms come out to be in the easy to remember“rule of thumb” 1:8:8².

Since a typical hadron therapy centre has 3-4 rooms, the figures of thetable say that a proton (carbon ion) centre would be needed for aboutevery 5 (40) million people. If the carbon centre is ‘dual’ and patientsare treated also with protons, the number of inhabitants who can beserved decreases from 40 to about 30 millions.

These arguments indicate that the development of hadron therapy requiresa change with respect to the presently dominating ‘paradigm’, which seesa multi-floor building serving 5 million people (or many more in thecarbon ion case) because it features one accelerator and 3-4 gantries.In the long term, a more flexible and patient-friendly paradigm willmost probably dominate being based on a single-room accelerator/gantrysystem for either protons or light ions (carbon), which is constructedon a relatively small area (about 500 m²)

At present, small or large radiotherapy departments run 1-2 or 5-6electron linacs respectively so that, on average, 8 conventional roomsare present in 3-4 hospitals covering a population of 1.5-2 millions. Tomaintain the proportions appearing in the last column of the table, twouses of such single-room facilities can be envisaged:

-   -   a single-room proton facility is “attached” to one of these        hospitals but also serves 2-3 others;    -   a single-room carbon linac facility is “attached” to an already        existing proton therapy centre which serves many million        inhabitants but accelerates carbon, and    -   possibly other light ions, to an energy which is not sufficient        to treat deep seated tumours.

Proton accelerators which are mounted on a gantry rotating around anaxis, and thus the patient, have been considered previously. In the 80'sa rotating 60 MeV superconducting cyclotron for neutron therapy wasconstructed by H. Blosser and collaborators for built for the HarperHospital (U.S. Pat. No. 4,641,104). Following this realization, morethan fifteen years ago a 250 MeV superconducting cyclotron for protontherapy was proposed (H. Blosser et al, Medical accelerator projects atMichigan State University, Proc. 1989 Particle Acceleration Conference,IEEE, 1989, 742-746). Recently the construction project of a single roomapparatus based on a rotating synchrocyclotron has been announced(http://web.mit.edu/newsoffice/2006/proton.html, press release of MIT,28 Aug. 2006).

SUMMARY OF THE INVENTION

The basic aim of the present invention is to propose facilities forhadron therapy based on a high frequency linac (or more than one linacsection) which is (are) mounted on a rotating gantry and used for theirradiation from more than one direction of a patient.

This aim is reached by a system or complex of ion accelerators with thefeatures of claim 1. Further developments are inferable from thedependent claims.

To answer the needs described above, according to the present invention,protons and/or ions are accelerated to the energy needed for therapy (orfor any other application) by one or more high-frequency linacsection(s). At least one of these sections is mounted on a gantry whichcan rotate around the target so that the optimal beam direction can bechosen. The injector of the moving linac (named here “pre-accelerator”)can be either a circular accelerator (cyclotron, synchrocyclotron, FFAGor other) or a low-velocity linac or a combination of two or more ofthese well known accelerators.

Moreover the ion beams produced by some of the components of thepre-accelerator can be used for other purposes, for instance to treatpatients or/and to produce radioisotopes for medical purposes or/and forindustrial applications. Typically the pre-accelerator is rigidly fixedon the floor supporting the rotating gantry, but it can also be, in partor fully, mounted on the gantry.

In cancer therapy a linac mounted on a gantry rotating around thepatient is a solution which is simpler, more flexible and surer than theones based on circular accelerators mounted on gantries. Indeed theoutput beam is pulsed with rates in the range 50-500 Hz and can be veryeasily coupled to an ‘active’ dose spreading system, since the particleenergy and the dose given to a voxel can be adjusted, electronically andin about 1 millisecond, from pulse to pulse (R. Zennaro, IDRA: DesignStudy of a Proton Therapy Facility, Beam Dynamics Newsletter, n. 36, p.62, April 2005). This unique property implies that there is no need forabsorbers to reduce the beam energy, as in fixed-energy cyclotrons. As aconsequence the unwanted production of intense and difficult to shieldneutron fluxes close to the patient is avoided.

A high-frequency linac is superior to the all other types of acceleratorbecause the beam energy can be varied from pulse to pulse together withthe number of particles do be delivered to the tumour target. The timeand intensity structure of the pulsed beam are particularly suited fordoses delivered in an ‘active’ way, for instance implementing either thetechniques of ‘spot scanning’, as in use at the PSI Centre, PaulScherrer Institute, Villigen, Switzerland (E. Pedroni et al, The 200 MeVproton therapy project at the Paul Scherrer Institute: conceptual designand practical realisation, Medical Physics, 22(1), (1995) 37), or of‘raster scanning’, as in use at the GSI Centre, Darmstadt, Germany (Th.Haberer, et al, Magnetic scanning system for heavy ion therapy, NuclearInstruments and Methods A 330 (1993) 296). As mentioned above, furtherfavorable developments of the invention are pointed out in the dependentclaims.

The use of the ion acceleration system for hadron therapy according tothe invention presents many important advantages. First of all theaccelerator is lighter with respect to existing cyclotrons andsynchrotrons, and is characterized by a modular structure composed ofthe same high technology equipment repeated almost without variation foreach accelerating module. Secondly, the proposed system is relativelycompact, so minimal volumes and installation surfaces are needed,therefore facilitating the installation in hospital centers. Moreover,the high frequency of the linac allows for a reduction in powerconsumption which reflects in reduced exploitation costs.

In summary, with respect to the hadron therapy facility either in use orconceived, the present invention allows 1) to build compact facilities2) having a single-room which 3) can be installed also in alreadyexisting medium sized hospitals leading so 4) to lead, due to therelatively low cost, to a wide spread diffusion of tumour hadrontherapy.

The disclosed system is dubbed TULIP for “TUrning LInac for Particletherapy”.

The linacs, disclosed in the documents WO 2004/054331 and U.S. Pat. No.6,888,326 B2 in the name of the Applicant, can be used as the highfrequency modular linacs which can be used for the present invention.Their content is hereby included for reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, details and characteristics of the ion accelerationsystem for hadron therapy according to the invention will furthermoreresult from the following description of examples of preferredembodiments of the invention, schematically illustrated in the annexeddrawings, in which:

FIGS. 1.a, 1.b, 1.c, 2 and 3 show block diagrams of various possibleembodiments of a ion acceleration system or complex for hadrontherapyaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The components of the complexes T of hadron accelerators shown in FIG.1.a, 1.b, and 1.c are the following:

-   1. ion source;-   2. Low Energy Beam Transport channel (LEBT);-   3. cyclotron (normal or superconducting) or FFAG (normal or    superconducting) or other circular accelerator;-   4. 4A and 4B: beams extracted from the circular accelerator 3 and    used for other purposes either in parallel or alternatively with the    gantry;-   5. Medium Energy Beam Transport channel (MEBT);-   6. first (I) linac section, at a frequency typically greater than 1    GHz, and beam transport magnetic channel;-   7. first Integrated Magnetic Transport Channel (1^(st) IMTC) made of    quadrupoles, bending magnet(s) and RF buncher(s) to transport, bend    and shape the hadron beam;-   8. second (II) linac section with a frequency that can be a multiple    of the one of the first linac section (I);-   9. second Integrated Magnetic Transport Channel (2^(nd) IMCT) made    of quadrupoles, bending magnet(s) and RF buncher(s) to transport,    bend and shape the hadron beam;-   10. third (III) linac section with a frequency that can be a    multiple of the one of the second linac section;-   11. scanning magnet(s), placed either upstream or at the centre or    downstream of item 12, to move transversally the hadron beam for an    ‘active’ delivery of the dose;-   12. third Integrated Magnetic Transport Channel (3^(rd) IMCT) made    of quadrupoles, large angle bending magnet(s) and RF buncher(s) to    transport, bend and shape the hadron beam;-   13. fourth (IV) linac section with a frequency that can be a    multiple of the one of the third linac section;-   14. in the case of ‘active’ delivery, scanning magnet(s) to move    transversally the hadron beam or, in the case of ‘passive’ delivery,    system of scatterer(s), absorber(s), filter(s) and collimator(s);-   15. monitoring system of the therapeutic beam.-   16. focus of the dose delivery system;-   17. metallic structure (gantry) partially or fully rotating around    an axis X and rigidly supporting the components 7-15.

Referring to the more general FIG. 1.a, according to the invention thehadron accelerator complex T includes in principle various kinds ofaccelerators serially connected, namely a circular accelerator 3 (whichcan be can be either at room temperature or superconducting) and anumber of linac sections (6, 8, 10, 13), possibly of increasingfrequencies so to have in the latter stages a higher gradient and thusreduce the overall dimensions of the system. To simplify the overallscheme some of the four linac sections may be absent and/or may beplaced in a topologically different set-up, as shown for instance inFIGS. 1.b and 1 c.

Each linac section is made of accelerating modules which can havestructures of the Drift Tube Linac (DTL) or Cell Coupled Linac (CCL)type according to the speed of the accelerated hadrons. Two of thesestructures are disclosed in the documents WO 2004/054331 and U.S. Pat.No. 6,888,326 B2 in the name of the Applicant and are here quoted andincorporated as a reference so that it is not necessary to furtherprovide details on the structures of the accelerating modules.

It has to be remarked that the output energy of the circular accelerator3 is usually fixed and therefore its value is chosen according to thedesired application and, more precisely, according to the type of centrethat one wants to develop and/or the use one possibly wants to make ofother extracted beams, exemplified by 4A and 4B in FIGS. 1.a and 1.c.The circular accelerator is fed by either an internal or external source1 via, usually, a low energy beam transport line 2. Its output beam canbe continuous or modulated at the repetition frequency of the linac(s).A beam at the exit of the circular accelerator 3 is transported to thegantry system by a magnetic channel made of bending magnets andquadrupoles and a linac section 6. The rest of the system is mounted onthe gantry 17. In some embodiments the circular accelerator 3 is notneeded and the linac 6 with its transport channel pre-accelerates thehadrons both for the uses exemplified by 4A and 4B and for the injectionin the 1^(st) IMTC 7. In other embodiments the circular accelerator isrigidly connected with the gantry, as indicated in FIG. 1.b.

The subsystems supported by the gantry and drawn in the FIGS. 1.a, 1.band 1.c are not necessarily all present in a single embodiment. Ingeneral the linac section producing the largest acceleration gradient isthe one indicated as 10 in the FIGS. 1.a, 1.b and 1.c.

The third Integrated Magnetic Transport Channel (3^(rd) IMCT) 12 directsthe focused particle beam to the patient and is an essential componentof the overall system. It is made of well known components (normal orsuperconducting) as quadrupoles and large angle bending magnet(s). Insome embodiments it can be followed by linac section 13 of FIG. 1.a. Thetwo scanning magnets 11 and/or 14 move the beam transversally either ina divergent or in a parallel configuration. They can be placed before,in the middle or after the 3^(rd) IMCT. These magnets when an ‘active’delivery system is used, define the dimensions of the irradiated field.In case of a ‘passive’ scattering the scanning magnets 11 and 14 are notneeded and the particles are spread out, moderated in energy andcollimated by well know components: scatterers, absorbers, filters,collimators etc.

In the illustrated Figures the sources of the RF power are not shown.They are typically high-frequency klystrons running at repetition rateslarger than 50 Hz. These devices can be either mounted on the gantry 17or are located outside the gantry and connected to the modules of theLinac via rotating wave-guide devices. These can be commercial rotatingradiofrequency power devices or consist of two rotating and closelycoupled mode converters facing one another and separated by a small gap.This invention differs from the development done at SLAC on 11.4 GHznon-rotating mode converters (V. A. Dolgashev et al, Design of CompactMulti-Megawatt Mode Converter, Slac-Pub-11782), which has beensubsequently scaled down for 3 GHz operation at the CERN CLIC testfacility (A. Grudiev, Development of a Novel RF Waveguide Vacuum Valve,EPAC 06, Edinburgh, UK, June 2006).

In the following, to complete the general description of the TULIPcomplex, two embodiments are given according to the invention.

In the first one protons are accelerated to 230 MeV adopting the schemeof FIG. 2. The protons produced by the source 1 are gated at 200 Hz andinjected by the LEBT 2 in a 24 MeV cyclotron 3. Only the II and IIIlinac sections (8 and 10) are present. They are both of the SCL SideCoupled Linac) type and are mounted on the gantry 17. They may bepowered by commercial radiofrequency amplifiers (klystron), as forexample those produced by the company Thales Electron Devices (78941Velizy, France) or CPI (Palo Alto, Calif. 94303-0750, USA).

For the transverse beam focusing, both linacs use very small commercialquadrupole permanent magnets (QPM), such that they can fit between twoconsecutive accelerating sections, forming an alternate focusing, FODOtype system.

In between linac 8 and linac 10 the Integrated Magnetic TransportChannel 9 (2^(nd) IMTC) is made of seven quadrupoles, Q, and two bendingmagnets (M2 together with M3) and contains a four-gap RF buncher, RB, tore-bunch longitudinally the beam which becomes continuous in the longdrift between linac 8 and linac 10. The bending magnets for thetransverse scanning, SM1 and SM2, are one upstream, 11, and the otherdownstream, 14, of the third Integrated Magnetic Transport Channel 12(3^(rd) IMCT made of M4 together with M5 and the quadrupoles Q) so thatthe average distance between the virtual focus of the therapeutic beamand the focal point 16 is about 3.5 metres. The irradiation field is20×20 cm². A dose of 2 grays can be delivered to a 1 litre tumour bypainting it about 20 times with the spot scanning technique in a coupleof minutes. This technique is optimal for the irradiation of movingorgans.

The main parameters of the embodiment shown in FIG. 2 are summarized inTable 1.

TABLE 1 Basic parameters of the embodiment of FIG. 2. General featuresTotal weight [tons] 80 Total length [m] 25 Approximate radius of thegantry system [m] 5.5 Total power [kW] 500 Magnets Dipole M1: angle[deg], radius of curvature [m] 20, 0.8 Dipoles M2, M3: angle [deg],radius of curvature [m] 92, 1.1 Dipoles M4, M5: angle [deg], radius ofcurvature [m] 53, 1.5 Number of quadrupole magnets, Q 14 Linac 8, IIFrequency [MHz] 2998 Length [m] 7.1 Number of modules 10 Repetition rate[Hz] 200 Input Energy [MeV] 24 Output Energy [MeV] 92 Duty Factor of theproton pulse at 200 Hz [%] 0.10 Linac 10, III Frequency [MHz] 2998Length [m] 12.8 Number of modules 12 Repetition rate [Hz] 200 InputEnergy [MeV] 92 Output Energy [MeV] 230 Duty Factor of the proton pulseat 200 Hz [%] 0.10 Re-buncher, RB Frequency [MHz] 2998 Number of gaps 4Scanning Magnets SM1, 11: maximum angle [mrad], dist. virtual focus to16, 4.2 isocenter [m] SM2, 14: maximum angle [mrad], dist. virtual focusto 37, 2.7 isocenter [m] Field at isocenter [cm × cm] 20 × 20

The acceptance of the linac system is such that a cyclotron current of15 μA is needed to obtain a maximum number of 2 10⁷ protons/pulse,corresponding at 200 Hz to a current of 0.6 nA. The cyclotron can easilydeliver a current 10 times larger but less than 1 nA is sufficient forthe multi-painting of 1 litre volume and a dose delivery rate of 1Gy/min.

In the embodiment shown in FIG. 3 the circular accelerator is thesuperconducting 300 MeV/u C⁶⁺ carbon ion cyclotron proposed by INFN—theItalian National Institute for Nuclear Physics (L. Calabretta et al, Anovel superconducting cyclotron for therapy and radioisotope production,Nuclear Instruments and Methods A562 (2006) 1009-1012) andcommercialized by the company IBA—Ion Beam Application from Belgium(http://www.iba.be/documents/contribute/PR-INFN-GB.pdf—IBA pressrelease, Hadrontherapy: The new 300 MeV/u superconducting cyclotrondeveloped by INFN will be commercialized by IBA”, Sep. 26, 2006).

The beams 4A and 4B of FIG. 3 are proton and carbon ion beams used fortherapy of deep seated tumours with protons (water range=35 cm) and ofshallow tumours with carbon ion (water range=17 cm). To treat deepseated tumours carbon ions have to have at least 400 MeV/u (27 cm range)and the present invention is particularly useful to fully exploit thepotential of a 230-300 MeV/u cyclotron for carbon ion therapy.

The magnetic rigidity of these carbon ions is about 2.5 times largerthan the one of 250 MeV protons, so that the dimensions and weights ofthe second embodiment of the invention are definitely larger than theones of the first. But this is not a too serious inconvenience sinceordinary gantries for carbon ions are already very large, weighty andcostly: the only known example is the one built for the HIT centre inHeidelberg which is 25 meter long, has a radius of 5 meters, weights 600tons and consumes about 400 kW (R. Fuchs et al, The heavy ion gantry ofthe HICAT facility, Proceedings of EPAC 2004, Lucerne, Switzerland). Thepresent invention allows to have (within about the same dimensions,weight and power) a booster accelerator that brings the carbon beam to400 MeV/u and a delivery system which is fully ‘active’ on a 20×20 cm²field.

In this embodiment, shown in FIG. 3, the first linac section 6 fixed onthe floor (FIG. 1.a) is not foreseen. The first Integrated MagneticTransport Channel (1^(st) IMTC) 7 is made of seven quadrupoles and twobending magnet(s) and sends the beam to the second linac section 8 whichis of the CCL type as in the first embodiment. The second IntegratedMagnetic Transport Channel (2^(nd) IMCT) and the third linac 10 are notforeseen. The geometry of the third Integrated Magnetic TransportChannel (3^(rd) IMCT) 12 and of the scanning magnet(s) 14 to movetransversally the hadron beam are similar to the ones of the firstembodiment, with dimensions scaled up by a factor 2.3 because of thelarger magnetic rigidity of the hadrons.

The main parameters of the embodiment shown in FIG. 3 are given in Table2.

TABLE 2 Basic parameters of the embodiment shown in FIG. 3 Generalfeatures Total weight [tons] 500 Total length [m] 33 Approximate radiusof the gantry system [m] 9.6 Total power [kW] 900 Magnets Dipoles M2,M3: angle [deg], radius of curvature [m] 10, 3.3 Dipoles M4, M5: angle[deg], radius of curvature [m] 55, 3.9 Number of quadrupole magnets, Q11 Linac 8, II Frequency [MHz] 2998 Length [m] 16.4 Number of modules 12Repetition rate [Hz] 400 Input Energy [MeV] 300 Output Energy [MeV] 400Duty Factor of the proton pulse at 200 Hz [%] 0.20 Scanning Magnets SM1,11: maximum angle [mrad], dist. virtual focus to  9, 7.9 isocenter [m]SM2, 14: maximum angle [mrad], dist. virtual focus to 29, 3.5 isocenter[m] Field at isocenter [cm × cm] 20 × 20

By adjusting the driving pulses of the klystrons it is possible tofinely vary about every millisecond the energy of the carbon beambetween 300 and 400 MeV/u, so that the water-range varies between 17 and27 cm. To reduce the average depth it is sufficient to insert anabsorber before IMTC 12.

From the structural and functional description of the variousembodiments of ion acceleration complexes for hadron therapy accordingto the invention it should be apparent that the proposed inventionefficiently achieves the stated aim and obtains the mentionedadvantages. With the proposed embodiments an important reduction indimensions may be obtained by using higher frequencies than the 2998 GHzadopted for the two described embodiments.

Those skilled in the art may introduce modifications and variations ofthe components and their combination, both in structure and/ordimensions, to adapt the invention to specific cases without departingfrom the scope of the present invention as described in the followingclaims.

LITERATURE

List of some publications in the sector of hadron therapy and relatedaccelerators:

-   U. Amaldi and M. Silari (Eds.), “The TERA Project and the Centre for    Oncological Hadrontherapy”, Vol. I and Vol. II, INFN, Frascati,    Italy, 1995. ISBN 88-86409-09-5. The “Blue Book”.-   U. Amaldi, M. Grandolfo and L. Picardi editors, “The RITA Network    and the Design of Compact Proton Accelerators”, INFN, Frascati,    1996, ISBN 88-86409-08-7. The “Green Book”.-   U. Amaldi (Ed.), “The National Centre for Oncological Hadrontherapy    at Mirasole”, INFN, Frascati, Italy, 1997, ISBN 88-86409-29-X. The    “Red Book”.-   U. Amaldi et al., “A Linac-booster for Protontherapy: Construction    and Tests of a Prototype”, Nuclear Instruments and Methods A    521 (2004) 512-529.-   L. Picardi, C. Ronsivalle and B. Spataro, “Design development of the    SCDTL structure for the TOP Linac”, Nuclear Instruments and Methods    A, 425 (1999) 8-22.-   Projet Etoile, rapport LYCEN 2002-01 (A,B,C) UCB-Lyon &    DAPNIA-02-06, DSM, CEA Saclay (2002).-   U. Amaldi and 5 co-authors, “Design of a Centre for Biologically    Optimized Light Ion Therapy in Stockholm”, Nuclear Instruments and    Methods B 184 (2001) 569-588.-   E. Takada et al., Proc. of the 13th Sympo. on Accel. Sci. and Tech.,    Osaka, Japan (2001) pp. 187-189 (HIMAC Project).-   A. Itano, Proc. of the 13th Sympo. on Accel. Sci. and Tech., Osaka,    Japan (2001) pp. 160-164 (HIMAC Project).-   WO 2004/054331 and U.S. Ser. No. 10/602,060 “Linac for ion beam    accelerator”. Inventors: Ugo Amaldi, Massimo Crescenti, Riccardo    Zennaro.-   R. Fuchs, U. Weinrich, P. Emde, “The heavy ion gantry of the HICAT    facility”, Proceedings of EPAC 2004, Lucerne, Switzerland.-   E. Pedroni, R. Bacher, H. Blattmann, T. Böhringer, A. Coray, A.    Lomax, S. Lin, G. Munkel, S. Scheib, U. Schneider and A. Tourovsky,    “The 200 MeV proton therapy project at the Paul Scherrer Institute:    conceptual design and practical realisation”, Medical Physics,    22(1) (1995) 37.-   Th. Haberer, W. Becher, D. Schardt and G. Kraft, “Magnetic scanning    system for heavy ion therapy”, Nuclear Instruments and Methods A    330 (1993) 296.

1. An acceleration system for charged nuclear particles with mass numberequal or greater than 1 for medical and/or other applications,comprising at least one radiofrequency (RF) linear accelereator,characterized by the fact that said at least one radiofrequency (RF)linear accelerator, i.e. linac or linac section, is mounted on amechanical gantry-like structure rotating around an axis used toirradiate the target/patient from more than one direction with a pulsedion beam.
 2. A system for ion acceleration according to claim 1,characterized by the fact that one or more particle accelerators, herenamed collectively pre-accelerator(s), impart(s) energy to the particlesproduced by an ion source before injecting the ion beam in the linac(s)mounted on the gantry-like structure.
 3. A system for ion accelerationaccording to claim 1, characterized by the fact of having on the gantrya system for ion beam delivery for medical or any other application. 4.A system for ion acceleration according to claim 1, characterized by thefact that the one or more linac section(s) is (are) mounted in anyposition on the gantry, may run at different frequencies and eachincludes a number of accelerating modules according to the consideredneeds.
 5. A system for ion acceleration according to claim 1,characterized by the fact that radio-frequency (RF) power generators areeither mounted on the gantry and directly connected to the modules ofthe linac section(s) or are located outside the isocentrical gantry-likestructure and connected to the linac section(s) via rotating wave-guidedevices, consisting of two coupled mode converters closely facing eachother and galvanically connected, or any other rotating radiofrequency(RF) power device.
 6. A system for ion acceleration according to claim2, characterized by the fact that the pre-accelerator is a conventionalor a superconducting cyclotron or a FFAG accelerator, both possiblyfollowed by a Linac.
 7. A system for ion acceleration according to claim2, characterized by the fact that the pre-accelerator is a conventionalor a superconducting Linac.
 8. A system for ion acceleration accordingto claim 2, characterized by the fact that the ion source and/or thepre-accelerator, or parts of it, are mounted on the isocentricalgantry-like structure.
 9. A system for ion acceleration according toclaim 2, characterized by the fact that it includes a source eithercontinuous or pulsed in accordance to the linac(s) repetition rate, forexample an ECR or EBIS or other type of ion source.
 10. A system for ionacceleration according to claim 1 characterized by the fact that theoutput energy of the beam is modulated by varying the input (RF) powerto the accelerating modules.
 11. A system for ion acceleration accordingto claim 1 characterized by the fact that the intensity of the linacoutput beam is modulated, also pulse-by-pulse, by the ion beamparameters at the ion source and/or at the pre-accelerator and/or by thebeam dynamics.
 12. Method of using a system for ion acceleration and itscomponents according to claim 1 in the medical field, in particular forthe production of radiopharmaceuticals and cancer radiation therapy,and/or for industrial purposes and/or in research in science and/or intechnological applications.